A lot of people have held that title before, acting as evangelists for science and discovery. Ben Franklin. Our buddy George Washington Carver. Stephen Jay Gould. Carl Sagan. Tyson's the latest standard-bearer, and two weeks ago he presided over an hourlong meditation on the birth and scope of the universe that was being broadcast on several networks at once.

Cosmos is an update of the beloved 1980 PBS series of the same name hosted by Sagan. The new edition is full of allusions to the old one. "We are made of star stuff," Tyson says in the first episode, repeating one of Sagan's most famous lines. A lot has been made of the fact that decades ago, Sagan — once the "It" Nerd himself — tried unsuccessfully to recruit the teenage Tyson to Cornell University.

Tyson's ascension to America's foremost nerd is a testament to his undeniable charisma and ability to make complicated ideas accessible to laypeople. But some of that's by default, because, really, who else might even be in contention for it? (Bill Nye, perhaps?)

But Tyson's current stature is unlikely for another reason: He's a black astrophysicist, as elusive a phenomenon as the Higgs boson.

"There are very, very few African-American astrophysics PhDs," Tyson told Alcalde, an alumni magazine for the University of Texas, Austin, where he studied for a time during graduate school. "That's for a reason. I was doing something people of my skin color were not supposed to do. So people who believed in me, like Sagan, were important."

Tyson has talked a lot about the casual racism he experienced at UT. ("I was stopped and questioned seven times by University police on my way into the physics building," he said. "Seven times. Zero times was I stopped going into the gym — and I went to the gym a lot. That says all you need to know about how welcome I felt at Texas." But he said that race was only at the edges of why he didn't excel there.)

Our play-cousins at Tell Me Morehave been paying a lot of attention to how underrepresented black folk are in STEM fields, but this is especially pronounced among astrophysicists. In 2012, the astrophysicist J.C. Holbrook tried to conduct a tally, and she could identify only a few dozen from the last six decades.

"Holbrook begins with some startling statistics: since 1955, only forty African-Americans have earned doctorates in astronomy or physics doing an astronomy dissertation. This means they comprise at most 2.47% of PhDs in astronomy. Out of 594 faculty at top 40 astronomy programs, 6 are African-American (1%). Notably, Hispanics fare no better, with 7 (1.2%), while Asians account for 42 of the 594, for 7.1%."

Holbrook was trying to figure out whether there were some specific strategies that had allowed the black folks who stuck around in the field to thrive. These are questions that Tyson himself has asked. While he sat on a panel for an event a few years ago, a questioner asked if there might be some "genetic reason" why there were so few women in science. That prompted Tyson to wonder aloud while his field looked the way it does.

"I've never been female, but I've been black all my life and so let me perhaps offer some insight from that perspective. I got to see how the world around me reacted to my expressions of these ambitions. All I can say that is the fact that I wanted to be a scientist, an astrophysicist was, hands-down, the path of most resistance through the forces of society. ... Now here I am, I think, one of the most visible scientists in the land. And I look behind me and I say, 'Where are the others who might have been this?' And they're not there. And I wonder: Where is the blood on the tracks that I happened to survive that others did not simply because of the forces of society that prevent it at every turn?"

Those questions are proving to be as difficult to resolve as any in physics.